An overlay deployment model is a commonly used deployment in wireless network applications. The overlay deployment model co-locates wireless control plane (WCP) functions and wireless switching plane (WSP) functions in a single device called a wireless controller (WC). A split plane architecture decouples the wireless control plane functions from the wireless switching plane functions into separate devices. Wireless control plane functions can be implemented in a virtual appliance or on hardware devices. A device that implements only wireless control plane functions is called a wireless control point.
Wireless switching plane functions can be integrated into a switch (e.g. stackable or core switches) when an enterprise is using a switching infrastructure. Wireless switching plane functions can also be provided on a wireless control plane managed wireless switching plane and an enterprise deployment that does not use a switching infrastructure.
In a centralized forwarding deployment, the WSP functions reside outside the access points (APs). An access point forwards traffic to the device that implements the WSP function. An overlay deployment model is an example of centralized forwarding. A split plane deployment model is also an example of centralized forwarding. These two deployment models are illustrated in FIGS. 1A and 1B.
In conventional WLAN deployments, access points terminate an access tunnel on the WSP component of the controller. The WSP component typically supports tens of physical ports and thousands of logical ports (access tunnels).
Access points tunnel client traffic to WSP components using CAPWAP encapsulation. The WSP components on the controller decapsulate the frame and submit the frame to forwarding logic. The WSP component also receives the frame from a wired network and submits the frame to forwarding logic.
Forwarding logic computes the transmitting ports based on the destination MAC address. The egress ports are a set of physical and logical ports in the network if the frame is destined towards a multicast group. One of the drawbacks in a centralized WLAN deployment can be that an increase in the number of logical ports (tunnels) may slow down the multicast forwarding and therefore affect multicast throughput of the system. For example, a copy of each multicast frame may need to be sent on each of the tunnels in a VLAN. This can consume processing cycles at the WSP thus bringing down the multicast throughput. Also, the multicast frames may be encapsulated and sent as unicast packets over the tunnels. This can increase the traffic by N times in the part of the network between the WSP and the AP, where N is the number of access tunnels.
Embodiments were conceived in light of the above-mentioned problems and limitations, among other things.